Impression-band for dentistry.



No. 644,705. Patented Mar. 6, I900. a. EVANS. IMPRESSIUN BAND FORDENTISTRY.

(Application fild Feb. 9, 1899.)

(No Model.)

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GEORGE EVANS, OF NElV YORK, N. Y., ASSIGNOR TO THE EVANS COMPANY, OFSAME PLACE.

IMPRESSION-BAND FOR DENTISTRY.

$PECIFIGATION forming part of Letters Patent No. 644,705, dated March 6,1 900.

Application filed February 9, 1 899.

To ttZZ whom it may concern.-

Be it known that I, GEORGE EvANs, a citizen of the United States,residing in the city and county of New York, borough of Manhattan, Stateof New York, have invented certain new and useful Improvements inImpression Collars or Bands for Dentistry; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

My invention relates to the art of obtaining the exact shape or contourof the neck and sides of a natural tooth or the root of a tooth inconnection with taking an 'impression of the tooth or root for thepurpose of obtaining a die or cast on which to construct an artificialcrown or gold cap or a metallic band or collar for supporting a denture.The method heretofore followed for this purpose consists in encirclingand adapting a strip of annealed copper of the proper width to the formof the neck or root. The strip is then removed, the ends touched withcement,then replaced upon the neck or root, and the ends cemented together, forming thus a band or collar. An impression is next taken ofthe tooth and the impression removed with the band in position in theimpression. A model made from the impression after the band or collar isremoved therefrom presents the exact form or contour of the neck orroot, and on this model the neck of the crown or gold cap or themetallic band or collar for supporting the denture is formed and fitsthe neck of the tooth or root accurately. This method is objectionablefor the reason that the impressionv collars or bands have to be made bythe den tist for each individual case and also because in removing theimpression material from the tooth or root the impression band or collaris apt to be moved or displaced from its correct position in theimpression material or to remain on the tooth or root in the mouth andnot come off with the impression, as intended. This result eitherimpairs the correctness of the impression or mold or entirely destroysit for the purpose it is intended to serve.

The object of my invention is to facilitate the work of the dentist inprocuring impres- Serial No. 705,076. (No model.)

sions of the teeth or roots and to guard against impairing or destroyingthe impressions by the bands or collars moving or remaining on the toothor root when the impression is 'removed.

To this end my invention consists in me tallic impression bands orcollars made in graded sizes to adapt them to be fitted to the normalvariations of natural teeth or roots and having on their exterior ears,lugs, or projections, formed on them or applied in any practical way.

In the accompanying drawings, Figure 1 represents an impression band orcollar with the projections formed on it; Fig. 2, the same with theprojection soldered on it. Fig. 3 represents the manner of applying theband or collar to the neck of a tooth; Fig. 4, the same invested withthe impression material. Fig. 5 shows the impression after it is removedfrom the tooth and with the band or collar remaining in the impression.

Referring to the drawings, A designates the impression collar or band.It is made from a strip of thin metal-copper, for example-with the endssoldered together and shaped to the general form or contour of the neckand sides of a tooth. On the opposite sides of this collar or band,about midway between the ends, are projections 17 b, which may be formedby making parallel slits d din the sides and pressing the parts 19between the slits outward, thus forming projections, ears,

or lugs that extend out from the surface of the side at about rightangles thereto. This is the preferred method of forming theseprojections; but Fig. 2 shows them formed by soldering pieces of metalof the proper form and size to the sides of the band or collar. It is tobe understood that I do not confine myself to any method of formingthese projections. The collars or bands thus constructed are to be madein various sizes to adapt them to fit the different teeth and the normalvariations in the shape and size of natural teeth, so that by properselection the dentist can obtain one suitable to any normal case thatwill require but the minimum of labor and time to be expended inadapting it and fitting it to the tooth under treatment.

These articles are used in the following manner: The dentist selects oneof the impression-collars of the right size, places it on the tooth B sothat the projections will be on the outside and inside, (called thelabial and lingual 0r palatal sides,) and fits it closely, as seen inFig. 3. An impression is then taken of the parts with some suitableimpression material E. As the impression material E is pressed over thetooth or root it is squeezed into or around the projections I) Z), whichthus become embedded in the material, and when the impression hardensand is removed the collar is drawn off the tooth with it, and remainingimmovable it retains the exact and correct position in the impression ormold. hen plaster or fusible metal is poured into the impression or moldafter the collar is removed therefrom, the parts of the cast or diecorresponding to the neck and sides of the tooth or root will have theexact shape of the neck and sides of the natural tooth or root and beproperly positioned with respect to the artificial crown or denture tobe mounted thereon.

I claim- As an article of manufacture a band or eollar for takingimpressions of the natural teeth or roots, adapted to be mounted on thetooth or root and made to conform thereto, and havin g projectionsextending out from and clear of its sides whereby when plaster is flaredaround the band and root or tooth the projec tions become embeddedtherein and thus pre vent the band from becoming displaced or misplacedwhen the plaster impression is removed from the tooth or root,substantially as specified.

In testimony that I claim the invention above set forth I do attix mysignature in pres-- ence of two witnesses.

GEORGE EVANS.

\Vitnesses:

JOHN D. FITZ GERALD, CHAS. H. DAY.

